ORLANDO, Fla. - A military veteran suspected in the Memorial Day weekend killings of three people in Florida has been cornered by a SWAT team in Tennessee, according to media reports on Tuesday.

Tennessee television station WBIR reported that a standoff began at about 11:30 a.m. local time at a building in West Knoxville.

David Smith, 27, who is described as delusional, is believed to have killed the three sometime between Saturday and Monday, Florida law enforcement officials said.

Smith is a U.S. Army veteran with the 82nd Airborne Division who served in Iraq and Afghanistan, said Polk County Sheriff Grady Judd.

"I can tell you this guy is super dangerous," Judd said at a news conference earlier on Tuesday, adding that officials believe he is armed and they are trying to get him to surrender.

Judd said Smith had been located after an overnight manhunt but refused to specify where.

The bodies were discovered by Smith's 14-year-old niece who had been away for the weekend on an ROTC trip and found her mother - Smith's sister - and two others dead when she returned. Smith also recently lived in the home.

"It was a very violent scene," Judd said.

Two of the dead were identified by Judd as Danyala Smith, 31, sister of the suspected shooter, and Nikosi Williams, 25, a visitor at the house. The third victim has not yet been identified.

The sheriff also said Smith left the military a decade ago, suffers from post-traumatic stress disorder and described him as a paranoid loner.

Smith had previously been hospitalized involuntarily for his mental condition, and was posting delusional statements on Facebook.

"I don't know who could have done more, but I know a lot of people in the family tried to help him," Judd said.